Method of increasing the effective strength of beams or rafters of wood



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METHOD OF INCREASING THE EFFECTIVE STRENGTH OF BEAIVIS OR RAFTERS OFWOOD OR OTHER MATERIALS USED IN BRIDGES AND OTHER STRUCTURES.

Specification of Letters Patent No. 3,095, dated May 19, 1843.

To all whom t may concern: f

Be it known that I, JOHN R.' RnMiNeToN, ot Lowndes county, in the Stateof Alabama, have invented a lIethod of Increasing the Effective Strengthoit Timbers or Beams Used in Bridges and other Structures; and I dohereby declare that the following is a full, clear, and exactdescription of the same.

The nature of my invention consists in soA arranging timbers or beams asto avoid their tendency to break in the middle of their length, and thisis eli'ected by extending the ends of the timbers beyond the points ci'support and there bracing or tying them down so as to render the pointsof support fulcra; the tendency to break in the middle of the length isthus in part transferred to the points of support,-for it Will beevident that thus supported the timbers can not break in the middleWithout breaking also at the two points of support. I shall proceed todescribe the application of this principle to bridges without trussframes.

In the accompanying drawings, which make a part of this specification,Figure lV is an isometrical projection of the bridge,

Fig. 2, a longitudinal section of one end,

and F ig. 3 a transverse section of the same. rI`his bridge is to beconstructed Without truss frames and made to depend for strength whollyupon longitudinal sleepers i z resting on piers Z) b constructed ofmasonry or timber. In the drawings they are represented as made oftimber, a cross sill -supported on two or more pil-es c c constitutingeach pier. These abut-ments or piers, are se braced b y inclined braces(Z d, as to retain their.relative position. The end of the sleeperswhich extend beyond the piers are tied down by cross beams g', g, andinclined braces f, f, or this can be ef- 'ected by bands of iron passingover the ends of the sleepers and bolted to the timbers of the piers orabutments, or fastened by being let into the masonry of the piers.

The great object of these ties is not only to support the Weight of themass of timber of the sleepersV and the flooring, &c.,

put thereon which tends to break the sleep- 'ers in the middle of theirlength but also to assist insupporting the Weight passing over thebridge and thus transfer a part of the tendency to break in the middleto the parts resting on the piers, so long as the ties are of sutcientstrength to prevent the ends of the sleepers from rising. It is Veryevident that this principle can be applied under various modication's,and to all purposes requiring either length or strength of timbers, orboth-and the many modifications of Which it is susceptible must be leftWith the constructor as circumstances may require. It may be appliedwith ointed piers as represented in the accompanyingdrawings, Fig. 4,which is a longitudinal elevation of this modiiication. supported on theinclined piers b, which incline inward, that is to say they are nearertrgether at their loWer'ends than at the top, so that the Weight of thesleepers and What Vmay be placed thereon' shall tend to separate thepiers at their upper ends, and thus stretch the sleepers longitudinally,the ends of the piers at the bottom being so formed and constructed asto permit sutiicient play for this purpose. The ties or braces to holdthe extremities of the sleepers which projectsrans ra'rn einen.

A is the sleeper,

beyond the piers being also modilied in the attachment as to effectthisend.

What I claim as my invention and desire to secure by Letters Patent is-`The method of increasing the etilective strength of timbers orsleepers, or preventing their tendency to break in the middle of theirlength by tying or bracing downtheir ends beyond the points of support,in manner and for the purpose substantially as herein described.

It is to be understood that this method of increasing the effectivestrength of beams is applicable to all kinds of material of f 'Whichbeams are made iin Various constructions.

' JOHN R. REMINGTON.

Witnesses:

DIXON H. LEWIS, CHS, M. KELLER.

